1. Field
The present invention relates to sheets, particularly sheets of fragile material of the glass type, equipped for being fixed to supports or to be joined together using joining elements.
2. Description of the Related Art
Such sheets are intended in particular for producing walls or fixtures and fittings, of a facade element or an internal arrangement, which are made up of substrates, particularly transparent substrates, for example glass substrates.
To these ends, these sheets have therefore to have holes at the fixing and/or connecting points. They may be reinforced, particularly using thermal or chemical tempering, in order to obtain the required mechanical strength (and the required thermal resistance if necessary). The holes have therefore to be made before the heat treatment operation.
Document DE 195 42 040 discloses a sheet of glass which, at its edge face, has a peripheral slot, this slot being intended to accept a joint, it being possible for the joint to be forcibly inserted into the slot or bonded or extruded into said slot.
The main disadvantage with this type of sheet lies, in particular, in the fact that the connection between the slot and its joint requires the use of an external agent or an external action.
In the case of adhesive bonding, the adhesive chosen needs to be applied beforehand to the faces of the joint and/or of the slot that are to be bonded together, then the faces of the joint and/or of the slot are brought into contact, the assembly not actually being mechanically secure until after a given curing time has elapsed.
This adhesive-bonding technique is dependent upon the time taken for the adhesive to cure, and upon the integrity of the adhesive over time, it being possible for the mechanical connection between the joint and its slot to deteriorate over time as a result in particular of aging of the adhesive (under the action of UV radiation for example) or as a result of inappropriate mechanical or chemical demands, of the detergent or solvent type, etc., on the joint.
German utility model DE 203 02 370 describes a connecting system for glass sheets, this connecting system allowing connection to be made using a joining element collaborating through retaining shapes made on the edges of the sheets of glass. These dovetail retaining shapes are inappropriate if, as is often the case, the sheet has to undergo a heat treatment in order to improve its mechanical properties, this typically being a tempering operation. Stress concentrations are then created in the angular parts and there is a risk that these stresses will be released, destroying the sheet of glass.
When the joint or connecting system is “force fitted” into the slot without any special retaining appendages, insertion is governed by the mechanical properties of the material of which the joint or connecting system is made, particularly the elastic deformation properties. Provided that the joint or connecting system is not mechanically stressed, it will remain in place in its slot, but if, as a result of aging of the material, mechanical stresses that are inappropriate in terms of their direction and/or in terms of their intensity are applied, a gap may open and cause the joint or connecting system to escape from its slot. In addition, it is found that “force-fitting” a part of the joint or connecting system type is not the optimum way of inserting such a component when the latter is supposed to be able to transmit loads.